B5-086 Lysosomal Disorders Flashcards
what enzyme is deficient in Tay-Sachs?
HeXosaminidase A
tAy-saX
what substrate accumulates in Tay-Sachs?
GM2 ganglioside
- progressive degeneration
- developmental delay
- hyperreflexia
- no hepatosplenomegaly
Tay-Sach’s
cherry red macula
2
Tay-Sachs
Neimann-Pick disease
onion skin lysosomes
Tay-Sachs
- episodic peripheral neuropathy
- angiokeratomas
- hypophrisis
early presentation
Fabry disease
progresses to renal failure and cardiovascular disease
fabry disease
what enzyme is deficient in fabry disease?
a-galactosidase A
what substrate accumulates in fabry disease?
globosides
FA: ceramide-trihexoside
central and peripheral demyelination with ataxia and dementia
metachromatic leukodystrophy
what enzyme is deficient in metachromatic leukodystrophy?
arylsuflatase A
what substrate accumulates in metachromatic leukodystrophy?
sulfatides
FA: cerebroside sulfate
- peripheral neuropathy
- destruction of oligodendrocytes
- developmental delay
- optic atrophy
- globoid cells
Krabbe disease
what enzyme is deficient in Krabbe disease?
galactosylceramidase
what substrate accumulates in Krabbe disease?
2
galactosylceramide and psychosine
forms globoid cells, damaging myelin
- hepatosplenomegaly
- pancytopenia
- osteoporosis
- AVN of femur
- bone crises
- Gaucher cells
Gaucher disease
what enzyme is deficient in gaucher disease?
glucocerebrosidase
what substrate accumulates in Gaucher disease?
glucocerebroside fibrils in macrophages
Gaucher cells
treat with recombinant glucocerebrosidase
Gaucher disease
- progressive neurodegeneration
- hepatosplenomegaly
- foam cells
- cherry-red macula
Neimann Pick
what enzyme is deficienct in Neimann-Pick disease?
spingomyelinase
what substrate accumulates in Neimann-Pick disease?
sphingomyelin
causes multi-organ failure
what enzyme is mutated in I cell disease?
GlcNAc phosphotransferase
- mutation in GlcNAc phosphotransferase
- accumulation of storage materials in lysosomes
I cell disease
- stops growth/delayed development
- joint/skeletal deformities
- psychomotor impairment
I cell disease
deposition of undigested dermatan and heparan sulfate in coronary arteries causing ischemia and early death
Hurler syndrome
treatment for Hurler syndrome
- bone marrow/cord blood transplant
- enzyme replacement therapy
what is the inheritance pattern of Fabry disease?
x linked
- reddish purple skin rash
- kidney/heart failure
- burning pain in lower extremities
Fabry disease
treatment for Fabry disease
enzyme replacement therapy
- demyelination of nerve cells
- progressive weakening of muscles
Krabbe disease
treatment for Krabbe disease?
umbilical cord blood/bone marrow transplant
slow progression only, does not reverse
treatment for metachromatic leukodystrophy?
gene therapy
CD34 cells genetically modified with ARSA gene
treatment must be done before significant accumulation
- startle response
- loss of motor skills
- seizures, hearing/vision loss, paralysis
Tay-Sachs
treatment for Tay-Sachs?
none
- hepatosplenomegaly
- psychomotor regression
- recurrent lung infection
- thrombocytopenia
Niemann-Pick Disease
treatment for Neimann-Pick?
recently approved ERT
- hepato and splenomegaly
- severe joint pain
- neurological symptoms
- bony abnormalities
Gaucher disease
most common lysosomal storage disease
Gaucher
“crumpled tissue paper” appearance
Gaucher cells
histiocytes in the spleen engorged with sphingomyelin
Neimann Pick
lysosomes are produced from
vesicles budding off the Golgi
what is the pathophysiology of the “cherry-red” macula?
surrounding ganglions become opaque due to accumulation of undigested gangliosides
caused by defects in GlcNac phosphotransferase
I cell disease
defective enzyme does not add on a phosphate to the glycosylated acid hydrolase protein resulting in extracellular trafficking where it is inactive
I cell disease
caused by defects in the sphingomelinase enzyme
Neimann-Pick
leads to accumulation of toxic levels of sphingomyelin, resulting in multi-organ failure
Neimann-Pick
recombinant enzyme that degrades sphingomyelin used to treat Neimann-Pick
olupidase alfa
caused by defects in alpha-galactosidase A
Fabry disease
accumulation of globosides within the cellular lysosomes disrupt cellular function causing pain in extremeties, angiokeratomas, and cornea vertillata
Fabry disease
caused by failure to digest glycosaminoglycans
mucopolysaccharidosis
- short stature
- corneal clouding
- poor performance in schools
- often consanguinous families
mucopolysaccharidosis
easiest way to confirm diagnosis of mucopolysaccharidosis?
urine test
- late-onset
- burning pain in extremities
- angiokeratomas
- corneal verticilatta
Fabry disease
- hepatosplenomegaly
- pancytopenia
- easy bruising
- “crumpled-tissue” cells
Gaucher disease
caused by defects in the GLA gene
Fabry
caused by defects in the GBA gene
gaucher
caused by defects in SMPD1
Neimann-Pick
- hepatosplenomegaly
- motor defects/regression
- cherry red macula
Neimann-Pick
- strong startle response
- cherry red macula
- motor defects/regression
Tay-Sachs
caused by a toxic build up of galactosylceramide
Krabbe
large, multi-nucleated globoid cells that interfere with the formation of myelin
Krabbe
causes demyelination of nerve cells and progressive failure of the nervous system
Krabbe